Behavioral and cellular pharmacology characterization of 17-cyclopropylmethyl-3,14β-dihydroxy-4,5α-epoxy-6α-(isoquinoline-3'-carboxamido)morphinan (NAQ) as a mu opioid receptor selective ligand (original) (raw)
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ACS chemical neuroscience, 2015
Mounting evidence has suggested that G protein-coupled receptors can be stabilized in multiple conformations in response to distinct ligands, which exert discrete functions through selective activation of various downstream signaling events. In accordance with this concept, we report biased signaling of one C6-heterocyclic substituted naltrexamine derivative, namely 17-cyclopropylmethyl-3,14β-dihydroxy-4,5α-epoxy-6β-(4'-pyridylcarboxamido)morphinan (NAP) at the mu opioid receptor (MOR). NAP acted as a low efficacy MOR partial agonist in the G protein-mediated [35S]GTPγS binding assay, whereas it did not significantly induce calcium flux or β-arrestin2 recruitment. In contrast, it potently blocked MOR full agonist-induced β-arrestin2 recruitment and translocation. Additionally, NAP dose-dependently antagonized MOR full agonist-induced intracellular calcium flux and β-arrestin2 recruitment. Further results in an isolated organ bath preparation confirmed that NAP reversed the morph...
Bentham Science Publishers
Although the µ opioid receptor (MOR) was pharmacologically and biochemically identified in binding studies forty years ago, its structure, function, and true complexity only have emerged after its cloning in 1993. Continuous efforts from many laboratories have greatly advanced our understanding of MORs, ranging from their anatomic distribution to cellular and molecular mechanisms, and from cell lines to in vivo systems. The MOR is recognized as the main target for effective pain relief, but its involvement in many other physiological functions has also been recognized. This review provides a synopsis on the history of research on MORs and ligands acting at the MOR with the focus on their clinical and potential use as therapeutic drugs, or as valuable research tools. Since the elucidation of the chemical structure of morphine and the characterization of endogenous opioid peptides, research has stimulated the development of new generations of MOR ligands with distinct pharmacological profiles (agonist, antagonist, mixed agonist/antagonist and partial agonist) or site of action (central/peripheral). Discovery of therapeutically useful morphine-like drugs and innovative drugs with new scaffolds, with several outstanding representatives, is discussed. Extensive efforts on modifications of endogenous peptides to attain stable and MOR selective analogs are overviewed with stimulating results for the development of peptide-based pharmaceuticals. With pharmacophore modeling as an important tool in drug discovery, application of modern computational methodologies for the development of morphinans as new MOR ligands is described. Moreover, the crystal structure of the MOR available today will enable the application of structurebased approaches to design better drugs for the management of pain, addiction and other human diseases, where MORs play a key role.
Bentham Science
Although the opioid receptor (MOR) was pharmacologically and biochemically identified in binding studies forty years ago, its structure, function, and true complexity only have emerged after its cloning in 1993. Continuous efforts from many laboratories have greatly advanced our understanding of MORs, ranging from their anatomic distribution to cellular and molecular mechanisms, and from cell lines to in vivo systems. The MOR is recognized as the main target for effective pain relief, but its involvement in many other physiological functions has also been recognized. This review provides a synopsis on the history of research on MORs and ligands acting at the MOR with the focus on their clinical and potential use as therapeutic drugs, or as valuable research tools. Since the elucidation of the chemical structure of morphine and the characterization of endogenous opioid peptides, research has stimulated the development of new generations of MOR ligands with distinct pharmacological profiles (agonist, antagonist, mixed agonist/antagonist and partial agonist) or site of action (central/peripheral). Discovery of therapeutically useful morphine-like drugs and innovative drugs with new scaffolds, with several outstanding representatives, is discussed. Extensive efforts on modifications of endogenous peptides to attain stable and MOR selective analogs are overviewed with stimulating results for the development of peptide-based pharmaceuticals. With pharmacophore modeling as an important tool in drug discovery, application of modern computational methodologies for the development of morphinans as new MOR ligands is described. Moreover, the crystal structure of the MOR available today will enable the application of structurebased approaches to design better drugs for the management of pain, addiction and other human diseases, where MORs play a key role.
Frontiers in Pain Research
Mu opioid receptor (MOPr) agonists are well-known and frequently used clinical analgesics but are also rewarding due to their highly addictive and often abusive properties. This may lead to opioid use disorder (OUD) a disorder that effects millions of people worldwide. Therefore, novel compounds are urgently needed to treat OUD. As opioids are effective analgesics and OUD often occurs in conjunction with chronic pain, these novel compounds may be opioids, but they must have a low abuse liability. This could be mediated by diminishing or slowing blood-brain barrier transport, slowing target receptor binding kinetics, and showing a long half-life. NKTR-181 is a PEGylated oxycodol and a MOPr agonist that has slowed blood-brain barrier transport, a long half-life, and diminished likeability in clinical trials. In this study, we examined the signaling and behavioral profile of NKTR-181 in comparison with oxycodone to determine whether further therapeutic development of this compound may ...
Molecular Pain, 2014
Background: Opioid analgesics are the most effective drugs for the treatment of moderate to severe pain. However, they also produce several adverse effects that can complicate pain management. The μ opioid (MOP) receptor, a G protein-coupled receptor, is recognized as the opioid receptor type which primarily mediates the pharmacological actions of clinically used opioid agonists. The morphinan class of analgesics including morphine and oxycodone are of main importance as therapeutically valuable drugs. Though the natural alkaloid morphine contains a C-6-hydroxyl group and the semisynthetic derivative oxycodone has a 6-carbonyl function, chemical approaches have uncovered that functionalizing position 6 gives rise to a range of diverse activities. Hence, position 6 of N-methylmorphinans is one of the most manipulated sites, and is established to play a key role in ligand binding at the MOP receptor, efficacy, signaling, and analgesic potency. We have earlier reported on a chemically innovative modification in oxycodone resulting in novel morphinans with 6-acrylonitrile incorporated substructures.
A Novel µ-Opioid Receptor Ligand with High In Vitro and In Vivo Agonist Efficacy
Current Medicinal Chemistry, 2012
The aims of this study were to synthesize 14-O-Methylmorphine-6-O-sulfate (14-O-MeM6SU) and examine its opioid properties (potency, affinity, efficacy) in receptor ligand binding and isolated tissues (mouse vas deferens, MVD and rat vas deferens, RVD bioassays). The results were then compared to the parent compounds morphine-6-O-sulfate (M6SU) and morphine, as well as theopioid receptor (MOR) selective agonist peptide [D-Ala 2 ,N-Me-Phe 4 ,Gly-ol 5 ]enkephalin (DAMGO). An additional objective was to compare the effect of subcutaneously (s.c.) or intracerebroventricularly (i.c.v.) administered 14-O-MeM6SU, M6SU and morphine in thermal nociception, rat tail-flick (RTF) test. In MVD, the EC50 (nM) value was 4.38 for 14-O-MeM6SU, 102.81 for M6SU, 346.63 for morphine and 238.47 for DAMGO. The effect of 14-O-MeM6SU and DAMGO was antagonized by naloxone (NAL) with Ke value 1-2.00 nM, similarly to DAMGO. The Emax values (%) were 99.10, 36.87, 42. 51 and 96.99 for 14-O-MeM6SU, M6SU, morphine and DAMGO, respectively. In RVD 14-O-MeM6SU and DAMGO but not M6SU or morphine showed agonist activity. In binding experiments the affinity of 14-O-MeM6SU, M6SU, morphine and DAMGO for MOR was 1.12, 11.48, 4.37 and 3.24 nM, respectively. The selectivity of 14-O-MeM6SU was /μ=269 and /μ= 9. In G-protein activation experiments, 14-O-MeM6SU and DAMGO showed higher Emax values than M6SU or morphine. S.c. or i.c.v-injected 14-O-MeM6SU, M6SU and morphine produced a dose and time-dependent increase in RTF response latency. 14-O-MeM6SU was the most potent. Our results showed that, introduction of 14-O-Me in M6SU increased the binding affinity, agonist potency, and most importantly, the intrinsic efficacy (Emax).
The Mu and Delta Opioid Receptors: Mixed Efficacy Ligands and Receptor Trafficking
2013
are deserving of thanks for all the training, assistance, and advice they have given me with regards to the pharmacological aspects of my thesis. I also want to thank all the members of the Mosberg and Traynor labs, past and present, for listening to my problems and returning to me advice and sympathy and the students of the Medicinal Chemistry department with whom I have commiserated and exulted, depending on the state of our research. I would also like to thank the members of my committee, Drs. John Traynor, Roger Sunahara, Ronald Woodard, Oleg Tsodikov, and James Woods. They have helped shape this project and given advice that has been exceedingly valuable. I also want to thank my funding sources, the Pharmacological Sciences Training Program, the Neuroscience Training Grant, and the Fred Lyons Fellowship, for financial support during my graduate school career, without which the research would not have been possible. Closer to home, I would like to thank my friends and family, both biological and found, my strong, beautiful, Barnard women, and the Michiganders who have welcomed us here in Ann Arbor. Without them, my life would be so much harder. And, last but definitely not least, I want to thank my spouse, Gabe Carlson, who has made my life so much better. iii TABLE OF CONTENTS ACKNOWLEDGEMENTS ii LIST OF TABLES viii LIST OF FIGURES ix LIST OF APPENDICES xi LIST OF ABBREVIATIONS xii ABSTRACT xvii CHAPTER LIST OF APPENDICES Appendix A. Failed Fluorescent Ligand Scaffolds Appendix B. The Minimal Functional Unit of the Mu Opioid Receptor is Monomeric 107 xii LIST OF ABBREVIATIONS [ 35 S]GTPγS [ 35 S] guanosine 5'-O-[gamma-thio]triphosphate 1Nal 1-naphthylalanine 2Nal 2-naphthylalanine AF488 Alexafluor 488 AF555 Alexafluor 555 AF647 Alexafluor 647 Aib 2-Aminoisobutyric acid Aic 2-aminoindane-2-carboxylic acid Ala Alanine Arg Arginine Asn Asparagine Asp Aspartate Boc Tert-butoxycarbonyl BOD647 Bodipy dye 647 BODTMRX Bodipy dye TMR-X C6 C6 rat gliomal cells CDOR Cyan fluorescent protein labeled delta opioid receptor xiii CFP Cyan fluorescent protein Cha Cyclohexylalanine CHO Chinese hamster ovary cells Cy3 Cyanine fluorescent dye 3 Cy5 Cyananine fluorescent dye 5 Cys Cysteine DAMGO [DAla 2 , N-MePhe 4 , Gly-ol]-enkephalin Dhp 3-(2,6-dimethyl-4-hydroxyphenyl)propanoic acid DIEA N,N-diisopropylethylamine DMF Dimethylformamide Dmt 2,6 dimethyl tyrosine dns does not stimulate DOR Delta opioid receptor DPDPE DPen 2,5-enkephalin DPN Diprenorphine ESI-MS Electrospray ionization mass spectrometry Et ethyl Fmoc 9-fluorenylmethyloxycarbonyl
Journal of Pharmacology and Experimental Therapeutics, 2011
Certain behavioral features of buprenorphine, including a bellshaped curve for antinociception and attenuation of alcohol consumption, are thought to be mediated by activation of nociceptin/orphanin FQ peptide (NOP) receptors, despite moderate affinity and low efficacy at NOP receptors. We hypothesized that ligands with buprenorphine's physical properties, but possessing increased NOP receptor affinity and efficacy, would improve the profile as a drug abuse medication and reduce addiction liability. Using this strategy, we designed several compounds with universally high affinity, i.e., less than 10 nM at , ␦, , and NOP receptors. Among these, (2S)-2-[(5R,6R,7R,14S)-N-cyclopropylmethyl-4,5-epoxy-6,14-ethano-3-hydroxy-6-methoxymorphinan-7-yl]-3,3-dimethylpentan-2-ol (BU08028) has high affinity at all opioid receptors and increased NOP receptor efficacy in vitro in the [ 35 S]GTP␥S bind-ing assay, however, while still being a partial agonist. In vivo, BU08028 was evaluated in an acute thermal antinociception assay, for its ability to induce conditioned place preference (CPP), and for its effect on cocaine-induced CPP. BU08028 is a very potent long-lasting analgesic. It produces an increase in locomotor activity and a significant CPP. As a pretreatment to cocaine, BU08028 does not alter cocaine CPP but causes a further increase in cocaine-induced locomotor activity. The analgesic, rewarding, and stimulant effects are probably caused by receptor stimulation. It is likely that with BU08028, a partial agonist at both NOP and receptors, -mediated activity overpowers NOPmediated effects. Thus, it is possible that a different buprenorphine analog that is a universal high-affinity opioid ligand but with "full agonist" activity at NOP may counteract traditional opioidmediated effects such as antinociception and reward.
ACS Chemical Biology, 2011
The development of tolerance to and dependence on opioid analgesics greatly reduces their longterm usefulness. Previous studies have demonstrated that co-administration of a mu opioid receptor (MOR) agonist and delta opioid receptor (DOR) antagonist can decrease MOR agonist induced tolerance and dependence development after chronic exposure. Clinically, a single ligand displaying multiple efficacies (e.g. MOR agonism concurrently with DOR antagonism) would be of increased value over two drugs administered simultaneously. Guided by modeling of receptorligand complexes we have developed a series of potent non-selective opioid tetrapeptides that have differing efficacy at MOR and DOR. In particular, our lead peptide (KSK-103) binds with equal affinity to MOR and DOR but acts as a MOR agonist with similar efficacy but greater potency than morphine and a DOR antagonist in cellular assays measuring both G protein stimulation and adenylyl cyclase inhibition.